Libchop is a set of utilities and library for data backup and distributed storage. Its main application is chop-backup, an encrypted backup program that supports data integrity checks, versioning at little cost, distribution among several sites, selective sharing of stored data, adaptive compression, and more. The library itself, which chop-backup builds upon, implements storage techniques such as content-based addressing, content hash keys, Merkle trees, similarity detection, and lossless compression. It makes it easy to combine them in different ways. The ‘chop-archiver’ and ‘chop-block-server’ tools, illustrated in the manual, provide direct access to these facilities from the command line. It is written in C and has Guile (Scheme) bindings.

se is a screen-oriented version of the classic UNIX text editor ed. The editor implements many of the commands of ed, but instead of being line-oriented, se is screen-oriented. The command syntax is very familiar to users who already know ed. If you get stuck, there is a built-in help system that describes many of the available commands. Many configurable options can be loaded from a .serc file. se can be run interactively or in a script via the included scriptse utility. The editor is portable across many platforms, supporting major Linux and BSD distributions as well as other systems like GNU, Minix, Haiku, OpenSolaris, and Cygwin.

GNU Mach is the microkernel upon which a GNU Hurd system is based. It provides an Inter Process Communication (IPC) mechanism which the Hurd uses to define interfaces for implementing in a distributed multi-server fashion the services a traditional operating system kernel provides. Mach is particularly well-suited for SMP and network cluster techniques. Thread support is provided at the kernel level, and the kernel itself takes advantage of that. Network transparency at the IPC level makes resources of the system available across machine boundaries.